Compact rolling mill for metal strands

ABSTRACT

A compact, space-saving rolling mill structure for metal strands, which mill is arranged between a strand casting apparatus and a second rolling mill equipped with high or low speed rollers is disclosed herein. The compact mill comprises a roller housing journaling rollers on hollow shafts which are driven through the output of angularly adjustable power transmission shafts. The power shafts derive their input from hollow worm wheels.

United States Patent [191 Moslener 1 3,765,212 [45l on. 16,1973

COMPACT ROLLING MILL FOR METAL STRANDS [7 5] Inventor: Jorn Moslener, Duisburg, Germany [73] Assignee: DEMAG Aktiengesellschaft,

' Duisburg, Germany [22] Filed: Aug. 14, 1972 [21] Appl. N0.: 280,249

[30] Foreign Application Priority Data Oct. 27, 1971 Germany P 21 53 5535 [52] US. Cl. 72/249 [51] Int. Cl B21b 35/00 [58] Field of Search... 72/249, 199

[56] References Cited UNITED STATES PATENTS 1,694,854 12/1928 Holmes 72/249 2,156,584 5/1939 Benedetti 72/249 X Primary ExaminerMilton S. Mehr Attorney-Hubert T. Mandeville et a1.

[57] ABSTRACT A compact, space-saving rolling mill structure for metal strands, which mill is arranged between a strand casting apparatus and a second rolling mill equipped with high or low speed rollers is disclosed herein, The compact mill comprises a roller housing journaling rollers on hollow shafts which are driven through the output of angularly adjustable power transmission shafts. The power shafts derive their input from hollow worm wheels.

11 Claims, 6 Drawing Figures PATENTEDntI sma SHEET 1 [IF 6 PATENTED w 6197s SHEET 30F 6 Y Y Figs PATENTEDBBT 1 ems SHEET S U? 6 COMPACT ROLLING MILL FOR METAL STRANDS BACKGROUND OF THE INVENTION Rolling mills with high-speed rollers are commonly used to manufacture high quality, profile strands, wires and strips having uniform and fine diameters. The metal material is processed in heavy rolling structures. High-speed rolling requires the addition of several mills, the spacing of which depends on the speed of the strand, its temperature and degree of molding as well as its maximum tensile strength. Rolling speed increases with decreasing strand diameter and increasing strand length, thus, rolling mill structures must be adapted to the specific dimensions of the metal material to be rolled. When manufacturing profile strands, this adaptation can be achieved by interchanging the rollers. It is not an uncommon practice to interchange entire rolling mill structures within refined iron and medium iron mill lines. The interchangeability of whole mill structures requires a special design of the mill drives. In many cases, unitary drives consisting of a motor and a gear are provided for each mill with the drives disposed perpendicular to the mill strand. This, of course, results in a considerable width of the mill line. Therefore, a mill building or a bay therein can usually house only one or perhaps two mill lines. Such a drive design prohibits the design of a plant having several mill strands in one single building or bay.

Rolling mills with low-speed rollers immediately follow a strand casting apparatus. The rollers run slowly, because their speed must be adapted to the speed of the casting process. While downstream high-speed rollers require a sufficient rolling pressure to mold the strand, upstream rolling structures, i.e., those immediately following the strand casting apparatus, must possess the greatest rolling pressures. Furthermore, the molding pressures for strand casting and the following rollers must be adjusted to the proper temperature distribution in the cast strand as well as to unspecified forces present in high-speed rolling which affect and propel the strand. Of course, the economy of cast rolling may be increased considerably with a multiple strand plant in which individual strands run parallel and are spaced slightly apart. Therefore, lateral arrangements of the rolling mill structures and their drives should be space saving for optimum operation.

Rolling mills with high-speed rollers for handling several strands have very little lateral space to accommodate motors and driving elements, since the space required for the driving elements cannot be easily reduced. This difficulty manifests itself even more when low-speed rollers are arranged behind strand casting apparatus in multiple strand plants.

Another difficulty arises from the necessary movement of the rolling mill structures when interchanging the rollers or substituting an entire mill. The design for lateral space saving of rolling mill drives may also complicate repair work which has to be done quickly during stoppages in the operation of the rolling mill. Furthermore, the compacting of rolling mill designs may make it difficult to employ an alternating arrangement of horizontal and vertical mills, which is often very desirable or necessary.

To improve mill designs with respect to the difficulties outlined above, the use of standardized units has been suggested. Such structures may be arranged immediately adjacent to and behind each other in order to obtain a space saving arrangement and interchangeability of the rollers, if the driving motor and gear are located primarily beneath the plant floor. This, however, creates problems, the foremost of which is the inaccessability of the driving elements.

A method is known to make such a rolling mill structure more easily accessible, viz., part of its drive is arranged to be detachable from the foundation and the rest of the drive together with a frame is arranged to be lifted vertically from the foundation. The saving of space in this kind of rolling mill design consists of the specific arrangement of the driving elements underneath the floor. of course, this driving element arrangement necessitates the removal of the rolling structure if maintenance personnel are to have access thereto. Furthermore, the arrangement of the driving element underneath the floor requires the installation of expensive, excavated foundations.

The alternating vertical/horizontal mill arrangement affects the exterior dimensions of the rolling structure in a certain unfavorable way. The height of the vertical rolling structure determines the extension of a similar rolling structure in the horizontal plane and therefore determines the lateral spacing of several parallel strand lines.

Another known layout of rolling mill structure, which is also provided with a driving element underneath the floor, incorporates driving elements located next to the roller housing. A connection between the driving elements under the floor and the roller shafts is established by means of a bevel gear. This arrangement requires a vertical driving shaft in the form of a spline shaft. Nevertheless, the access to the driving elements underneath the floor is still rather difficult.

SUMMARY OF THE PRESENT INVENTION The object of this invention is to provide a rolling mill structure for high speed and low speed rollers which has a very compact layout. The new rolling mill structure is easily interchangeable in multiple strand wire and refined iron mill lines, as well as in strip and girder mill lines, and its compact design makes it suitable for use immediately downstream of a strand casting apparatus in multiple strand casting plants.

A futher objective of the invention is to design a compact rolling structure having an equally compact driving element which is not arranged under the plant floor and which also permits a compact, parallel arrangement of several rolling structures in a row for several parallel strands. The new rolling structure is suitable for installation in vertical position (horizontal rollers) with respect to strand direction within a multiple strand plant. The structure of the invention readily accommodates the required interchanging of rollers as well as the easy maintenance of the driving elements. Furthermore, the invention provides for a separate roller housing and roller drive housing, each of which is independently removable and installable in the rolling struc ture.

In accordance with the principles of the invention, the objectives are achieved by the provision of hollow rollers driven through corresponding hollow gears which are not involved in the start-up motion, and by the internal connection of each roller with each gear in the cavities thereof by means of flexible (angularly adjustable) shafts and universal joints. Thus, the unique,

compact design of this rolling structure is achieved by the interior arrangement of the driving shafts, whereby the driving gear can be brought extremely close to the roller housing. After removing the driving shafts from their cavities, the rollers as well as parts of the driving elements may be dismantled without having to move one of the two separate structural units, roller and driving gear housings, respectively. In this manner, it is possible to eliminate the use of a driving element arrangement disposed below the floor. Hence, the foundations for the new structures may be very simple and inexpensive. Should the removal of the roller structure be desired, it may be simply accomplished. Driving elements are even more easily accessible with regard to the gear than in the above-mentioned sub-floor arrangements. Thus, the driving gear is arranged next to the roller housing, while the driving motor is arranged within the remaining spaces between the strands to be rolled in a manner whereby its driving shaft is parallel to the strand axes.

The arrangement of the driving gear adjacent to the roller housing may be effected within an even smaller distance if the connection between roller and shaft from point of entry of the shaft is moved towards the interior of the cavity. If required, the driving shafts may be longer so that only small angular movements are necessary when driving the rollers. The connection between roller and shaft or between gear and shaft is advantageously and desirably in the form of an arc gear coupling. If the deflection angle of the shaft axis with respect to the roller axis is sufficiently small, arc gear couplings are very durable.

In accordance with a further aspect of the invention, the gear pinions are in hollow worm wheels and the tooth engagement planes of the worm wheels and the corresponding worms are parallel to the rolling strand axes. The use of worm gears has a particular advantage made possible by the exterior roller diameter. If the exterior diameter of the worm wheel corresponds approximately to the exterior diameter of a roller, worm wheels may be readily accommodated, in contrast to the familiar bevel gears, in a narrow space running parallel to the lateral surface of the roller housing. The introduction of the torque from the motor in worm gears parallel to the strand direction presents a very favorable use of the available space between two adjacent rolling strands.

Furthermore, it is advantageous to engage the two worm gears provided for one roller pair with a common worm. This again saves space and, at the same time, guarantees a simple synchronization of the transmission of rotation forces to the rollers. Worm gears may also be used favorably in an alternative embodiment of this invention in which the outer radius of the worm wheel is greater than half of the distance between the two axes, and the worm wheels are laterally offset and each worm wheel engages with a worm. This arrangement is advantageous for the transmission of a driving torque for high rolling pressures. Also, this form of the invention aids in saving space, since the worm wheels designed for high torque transmission have a large circumference, which would ordinarily require a greater height within the gear box. Moreover, this arrangement accommodates a worm wheel diameter greater than the roller diameter.

In another embodiment of the invention, gear pinions, consisting of hollow, meshing spur gears, one of which is solidly connected with one coaxial worm wheel, are provided. This layout requires only one worm gear, whereby even higher torque may be transmitted by a worm wheel with large diameter to the rollers through spur gears. The spur gears provide the necessary synchronization and their diameters may be equal to the roller diameters, whereby the worm wheel diameter may be considerably larger than both the roller and spur gear diameters.

Axial movement of the shafts in the hollow gears and rollers is limited by alignment devices which ensure spherical support of the shafts within the rollers and gear pinions. One especially desirable embodiment provides for connections inside the hollow gear pinions and/or rollers permitting two angular movements for shafts extending in opposite directions in the cavity. Thus, it is possible to drive two adjacent rolling structures for different rolling strands with only one driving element, as desired. The rolling structure according to the invention is therefore especially suitable for multiple strand mills or multiple strand casting plants.

In accordance with the invention, the driving gear does not necessarily have to be attached to the roller housing in a vertical position. The gear can also be constructed as a modular type structural unit which can be inserted into special guides and removed as well from guides which are provided for the units above the roller housing. This type of arrangement is also very practical when used under the roller housing, although the latter arrangement is by no means the same as the abovedescribed arrangement of the driving element underneath the floor, because such a modular unit, after removal of the flexible shafts, may itself be removed without difficulty. Thus, the drive unit is readily accessible. It is also possible to mount the driving motor to such a unit and to provide special connectors which permit the quick installation and removal of the units.

Finally, a motor with gear may be arranged ahead of each roller housing and the gear casing may be connected with the part of the roller housing accommodating the bearing.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, plan view of a casting-rolling plant having three strands;

FIG. 2 is a schematic, side elevational view of one of the three strands showing a horizontal/vertical structural mill arrangement;

FIG. 3 is a cross-sectional view of a rolling mill structure according to the invention (as a horizontal rolling structure);

FIG. 4 is a first alternate embodiment of drive gearing for the mill of FIG. 3;

FIG. 5 is a second alternate embodiment of drive gearing of the mill of FIG. 3; and

FIG. 6 is a third alternate embodiment of the drive gearing of the mill of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, the rolling mill of the invention is shown in a multiple strand plant, in which multiple cast strands 1, 2 and 3 are shown leaving, in arrow direction, a strand casting device (not shown). The strand casting device is of the usual sort and has a casting ladle from which the molten material is poured into a distributor from which it continues to flow in adjacent strand casting chills (not shown). The thus formed metal strands 1-3 are further cooled and, as they leave the cooling line, they are introduced into the horizontal rolling mill structures 4, 5, and 6, of the invention, at

inside and outside molding temperatures suitable for the rolling process. The rolling structures indicated are gauged rolling structures; it is, however, also possible to use structures for open rollers. The metal strands initially molded in these rolling mills 4-6 are further molded in successive vertical rolling mills 7, 8, and 9. The vertical rolling mills 7-9 are illustrated, but drives for their rollers are not. FIG. 1 also shows a starter mechanism in these rolling mills which is not part of the subject invention. The driving elements for rolling mills 4-6 are driving mechanisms 10 and 11 located between the roller housings or pairs of supports 4a, 5a and 5a, 6a, respectively. Driving motors 14 and 15 are connected to these driving mechanisms through driving shafts disposed along axes 12 and 13.

FIG. 2 shows, in side elevation, the vertical rolling mill 8 and the horizontal rolling mill 5. The cast strand 2 to be rolled travels, in arrow direction, consecutively through rolling mills 5 and.8. The start-up elements for the horizontal rolling mill 5 are not an object of this invention and are, therefore, not described in detail. However, FIG. 2 shows the close succession of the horizontal rolling mill 5 and the vertical rolling mill 8. The cast strand 2 (as well as cast strands 1 and 3) are basically enclosed by roller housings or supports 4a, 5a and 6a, as shown.

FIG. 3 shows the horizontal rolling structure 5 (identical to mills 4 and 6) in a cross-sectional view taken perpendicular to the axis of the mill strand 16, whereby the driving component 10 (motor is not shown) is indicated in cross section accordingly. In the roller blocks or housings 5a, 5b, roller bearings 17 are provided for roller shafts 18. The rollers are hollow and are, therefore, provided with cylindrical cavities 21. Each cavity 21 may be continuous or it may be divided by diaphragms into individual sections, as long as the angular travel of shafts 22, 23 is accommodated. There are power and form connected, i;e., universal couplings 24 provided between shafts 22, 23 and rollers 19, 20, respectively. In the example shown, these are in the form of so-called arc gear couplings. Shafts 22, 23 are equipped with spur gear elements 25, and the cavities 21 of the rollers 19, are equipped with corresponding mating hollow gear teeth 26. The shafts 22, 23 have spherical heads 27 at opposite ends which are limited axially by spherical stops 28, which stops 28 are integral with plugs 29 which cover the end cavity openings in the gears and rollers.

FIG. 3 clearly depicts an essential element of the invention, namely, that the cavity 21 facilities the con trolled transfer of heat coming from east strand 2 and going through the roller 19 and roller rim 19a, thereby contributing to the maintenance of the cavity 21 temperature at an appropriate and predetermined level. Thistmay be directly effected by heating the cavity with air or by providing a liquid cooling depending on the precise temperature required in the roller rim 19a.

The driving element 10 has a design, as shown in FIG. 3, with respect to the bearings for rollers 19, 20. Shafts 22, 23 also form a power and form connected, i.e., universal coupling 24 of the type described previously. The gear pinions 30, 31 are central, solidly connected parts of the worm wheels 32, 33. Both worm wheels are driven by a worm 34, on the axis of which is the drive shaft from the motor 14. It is advantageous that the worm 34 is also located on the horizontal axis 35 of strand 16. This position guarantees a small driving angle 36 of shafts 22, 23, respectively, towards the roller rotation axes 37. It will be understood and appreciated that the design of the rolling structures, in accordance with the invention, permits an extremely compact construction, particularly when the tooth engagement plane 38 of the worm wheels 32, 33 and the worm 34 is in a parallel relation with strand 16.

FIG. 4 shows the driving element 10 designed in a somewhat modified form from that shown in FIG. 3. The driving element 10 and its housing 10a are again supported on a frame 39 to which roller support blocks 4a, 5a, and 6a are also secured. According to the arrangement of FIG. 4, the worm wheels 32, 33 are associated with worms 34a, 3412, respectively. Thus, both engagement planes 38a and 38b are offset from the vertical centerline of the housing 10. Worms 34a and 34b may be separately driven by small synchronized electric motors.

FIG. 5 shows a single worm 40 meshing with a worm wheel 41 which is attached solidly to a shaft 42 ofa hollow pinion 43. The cavities 21 remain otherwise the same as previously described. It is characteristic that the universal couplings 24 for each of the shafts 22, 23 are disposed at the remote ends of the cavities in the rollers and driving gears in order to obtain the minimum drive angle 36 of shafts 22, 23.

FIG. 6 illustrates a most advantageous embodiment of the compact rolling structure of the invention. The distance between roller drive 10 and the roller housing or blocks 5a, 5b is reduced to zero. Consequently, castings 10a of the driving element 10 are directly, rigidly attached to roller blocks 5a, 5b. This results in some remarkable advantages. Shafts 22 and 23 may berelatively short. Despite the decreased length, a relatively small driving angle 36 is obtained. Furthermore, the size of worm wheels 32, 33 may be virtually the same as or smaller than the diameters of the hollow rollers 19, 20.

The driving element 10 shown in FIG. 6 is particularly suitable for a rolling mill which is equipped with movable roller blocks 5a, 5b. Thus, the worm gears are placed in separate casings 45a, 45b for separate attachment to the roller housing blocks 5a, 5b.

It should be understood, of course, that the specific forms of the compact roller mill invention herein illustrated and described are intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

I claim:

1. A compact rolling mill for a metal strand (16) trav-' eling along a predetermined longitudinal axis, which mill is arranged between a downstream rolling mill and a strand casting apparatus, said compact mill including a roller housing means supporting a pair of rollers; a roller drive means including a motor and driving gear means; angularly adjustable drive shafts transmitting torque from said roller drive means to said roller, said compact mill further characterized in that a. said rollers (19, 20) and said driving gear means (30, 31; 32, 33; 43, 44) are not involved in the start-up motion and are hollow, defining cavities (21) therein;

b. said shafts 22, 23) communicate between the cavities (21) in each roller (19, and in said driving gear means; and

c. universal coupling means (24) permitting angular movements of said shafts with respect to said roller axes connect said shafts to said hollow rollers and to said gear means.

2. A rolling mill in accordance with claim 1, in which a. said universal coupling means (24) is disposed interiorly of each cavity (21) remotely of the point of entry of the shaft therein.

3. A rolling mill in accordance with claim 1, in which a. said universal coupling means (24) is an arc gear coupling.

4. A rolling mill in accordance with claim 1, in which a. said driving gear means includes hollow worm wheels (30, 31; 32, 33) and corresponding worms;

b. the tooth engagement planes of said worm wheels (30, 31) with said corresponding worms (34; 34a, 34b; 40) are parallel to the axis of the traveling strand (16).

5. A rolling mill in accordance with claim 1, in which a. said worm wheels (30, 31) are provided for one roller pair (19, 20) and engage only a single mutual worm (34).

6. A rolling mill in accordance with claim 1, in which a. the outer radius of said worm wheels (32, 33) is greater than half of the distance between the two axes;

b. said worm wheels (32, 33) are laterally offset; and

c. each of said worm wheels engages a separate worm 8 (34a, 34b). 7. A rolling mill in accordance with claim 1, in which a. said driving gear means include hollow, meshing spur gears (43, 44); b. one of said spur gears (43) is solidly connected with a single coaxial worm wheel (41); c. a worm (40) parallel with the axis of said strand 16 drives said worm wheel (41). 8. A rolling mill in accordance with claim 1, which further includes a. plural means for aligning and limiting axial movement of said shafts (22, 23) in said cavities (21) are disposed in said cavities. 9. A rolling mill in accordance with claim 8, in which a. said shafts (22, 23) have spherical supports (27, 28) within said rollers (19,20) and within said gear means (30, 31; 32, 33; 43,44). 10. A rolling mill in accordance with claim 1, in which a. said coupling means (24) are disposed within said hollow gears (30, 31; 32, 33; 43, 44) and rollers (19, 20) to accommodate angular movements of said shafts (22, 23); b. said shafts (22, 23) extend between opposite ends of the cavities (21). 11. A rolling mill in accordance with claim 1, in which a. a motor with a gear (10) is arranged upstream of each roller pair (19, 20); b. a gear casing (45a, 45b) is connected with the part of the roller housing (5a, 5b) accommodating a bearing (17). 

1. A compact rolling mill for a metal strand (16) traveling along a predetermined longitudinal axis, which mill is arranged between a downstream rolling mill and a strand casting apparatus, said compact mill including a roller housing means supporting a pair of rollers; a roller drive means including a motor and driving gear means; angularly adjustable drive shafts transmitting torque from said roller drive means to said roller, said compact mill further characterized in that a. said rollers (19, 20) and said driving gear means (30, 31; 32, 33; 43, 44) are not involved in the start-up motion and are hollow, defining cavities (21) therein; b. said shafts (22, 23) communicate between the cavities (21) in each roller (19, 20) and in said driving gear means; and c. universal coupling means (24) permitting angular movements of said shafts with respect to said roller axes connect said shafts to said hollow rollers and to said gear means.
 2. A rolling mill in accordance with claim 1, in which a. said universal coupling means (24) is disposed interiorly of each cavity (21) remotely of the point of entry of the shaft therein.
 3. A rolling mill in accordance with claim 1, in which a. said universal coupling means (24) is an arc gear coupling.
 4. A rolling mill in accordance with claim 1, in which a. said driving gear means includes hollow worm wheels (30, 31; 32, 33) and corresponding worms; b. the tooth engagement planes of said worm wheels (30, 31) with said corresponding worms (34; 34a, 34b; 40) are parallel to the axis of the traveling strand (16).
 5. A rolling mill in accordance with claim 1, in which a. said worm wheels (30, 31) are provided for one roller pair (19, 20) and engage only a single mutual worm (34).
 6. A rolling mill in accordance with claim 1, in which a. the outer radius of said worm wheels (32, 33) is greater than half of the distance between the two axes; b. said worm wheels (32, 33) are laterally offset; and c. each of said worm wheels engages a separate worm (34a, 34b).
 7. A rolling mill in accordance with claim 1, in which a. said driving gear means include hollow, meshing spur gears (43, 44); b. one of said spur gears (43) is solidly connected with a single coaxial worm wheel (41); c. a worm (40) parallel with the axis of said strand 16 drives said worm wheel (41).
 8. A rolling mill in accordance with claim 1, which further includes a. plural means for aligning and limiting axial movement of said shafts (22, 23) in said cavities (21) are disposed in said cavities.
 9. A rolling mill in accordance with claim 8, in which a. said shafts (22, 23) have spherical supports (27, 28) within said rollers (19,20) and within said gear means (30, 31; 32, 33; 43,44).
 10. A rolling mill in accordance with claim 1, in wHich a. said coupling means (24) are disposed within said hollow gears (30, 31; 32, 33; 43, 44) and rollers (19, 20) to accommodate angular movements of said shafts (22, 23); b. said shafts (22, 23) extend between opposite ends of the cavities (21).
 11. A rolling mill in accordance with claim 1, in which a. a motor with a gear (10) is arranged upstream of each roller pair (19, 20); b. a gear casing (45a, 45b) is connected with the part of the roller housing (5a, 5b) accommodating a bearing (17). 